This invention relates generally to a one-piece molded fluid filter, and a mold structure for making the same. More particularly, the invention is directed to an injection-molded in-line fluid filter of relatively small size.
Heretofore, in-line fluid filters have been provided for the filtering of various kinds of fluid. One such use is in a hydraulic system for filtering the the hydraulic fluid as it flows through the system. One of the prior art devices used incorporates a nylon mesh which is generally planar or flat and then rolled up into a cylindrical configuration. The cylindrical nylon mesh is then inserted into an insert mold of the desired configuration and plastic reinforcing means or end fitting are formed. One of the disadvantages of the prior art filter structure is that the nylon mesh is extremely fragile and difficult to handle. Secondary molding operations are relatively expensive and lead to many problems.
Another common problem is the molding of a relatively small, intricate configuration required to form the fine mech for the filter. Many times the sections of the mold are too small to fill with resin and hence leave voids in the filter. This causes many rejects to be formed during the manufacturing operation. Furthermore, the tooling itself for forming a mold of intricate configuration is expensive and time-consuming.
Another problem with prior art filters is that they are generally formed of flat screen-like webs. Therefore particulate matter tends to clog the filter completely against fluid flow. Also, because of the configuration of the in-line fluid filters heretofore provided, turbulent fluid flow is obtained through the filter thereby increasing the in-line fluid resistance.